Most commercial properties include a number of building systems that monitor and regulate various functions of the building for the comfort and well-being of the occupants. These building systems include security systems, fire control systems, elevator systems, and/or building environmental system.
A building environmental system regulates the temperature and flow of air throughout a building. The air conditioning for a building typically includes one or more chillers for cooling air and one or more heaters for heating air. Fans distribute air conditioned by a chiller or a heater into a duct system that directs the flow of air to the various rooms of a building. Dampers located within the duct system may be opened or closed by actuators. Also, the speed of a motor that drives a fan is controlled to regulate air flow within the system. An important component of a building environmental management system is the control system that varies the fan motor speed and the position of the various dampers to maintain the desired conditions within the building.
Energy Service Companies (ESCO) currently undertake projects, frequently referred to as performance contracts, which guarantee a specific level of performance for building environmental systems sold to clients. The performance relates to improved facility operations which generate reduced operating costs for the client. The ESCO typically identifies the amount of reduction in operating cost which will occur, i.e., the energy or cost savings, but also may guarantee to the client that the energy or cost savings will occur. After installation of a building environmental system or energy conservation measure, to verify that the energy and cost savings are actually occurring, the energy usage of the facility after the retrofits is compared to the energy usage prior to the retrofits.
However, conventional computer software packages that calculate the energy and cost savings have only a limited number of variables that can be applied to reflect weather and usage changes. For example, energy and cost savings software may be limited to accepting only monthly utility or meter data. As a result, the conventional computer software packages produce energy and cost savings calculations that may have unacceptably high error rates. Unreliable energy and cost savings calculations may prevent the accurate calculation of energy and cost savings for energy conservation measures and building environmental systems installed at customer locations. Thus, the energy and money saved by the energy conservation projects, such as the savings required by a performance contract, cannot be easily and reliably proven. Inaccurate cost savings calculations also may hinder reliable financial planning as the actual amount of energy expended, as well as the associated cost for each unit of energy, cannot be timely ascertained.